晋西黄土区坡面糙率的研究

Manning roughness of sloping ground in the loess area of west Shanxi Province.

坡面糙率是研究地表径流最为重要的参数之一,对坡面水文过程和土壤侵蚀过程模拟具有重要意义.该文采用野外实地冲刷水槽法,在测定不同地类地表糙率的基础上,研究了地表鲜草量、枯枝落叶量和地表硬度对地表糙率的影响,并探讨了地表糙率与地表径流泥沙含量的关系.研究结果表明,不同地类地表糙率差异显著;地表糙率与鲜草量成线性关系;枯枝落叶对地表糙率的影响存在极值;地表糙率随土壤硬度的增加而减小,且成幂函数关系;地表径流的泥沙含量随地表糙率的增加而减小,二者成对数关系.

As a predominant parameter of surface runoff, Manning roughness is quite important in simulating hydrology process and soil erosion. Using the method of field scouring flume, the experiment on the effects of the fresh grass yield, litter amount and the soil hardness on Manning roughness in different land types was carried out, and the relationship between Manning roughness and sediment concentration of surface runoff was also explored. Results show that Manning roughness varies significantly among different land types. Manning roughness increases linearly with the increase of fresh grass yield and decreases exponentially as soil hardness increases. Under certain discharge, Manning roughness increases within a limit as litter amount increases. Sediment concentration of the surface runoff decreases as Manning roughness increases, and this can be described by logarithm function.